Calculation method of ship collision force on bridge using artificial neural network

Ship collision on bridge is a dynamic process featured by high nonlinearity and instantaneity. Calculating ship-bridge collision force typically involves either the use of design-specification-stipulated equivalent static load, or the use of finite element method （FEM） which is more time-consuming and requires supercomputing resources. In this paper, we proposed an alternative approach that combines FEM with artificial neural network （ANN）. The radial basis function neural network （RBFNN） employed for calculating the impact force in consideration of ship-bridge collision mechanics. With ship velocity and mass as the input vectors and ship collision force as the output vector, the neural networks for different network parameters are trained by the learning samples obtained from finite element simulation results. The error analyses of the learning and testing samples show that the proposed RBFNN is accurate enough to calculate ship-bridge collision force. The input-output relationship obtained by the RBFNN is essentially consistent with the typical empirical formulae. Finally, a special toolbox is developed for calculation effi- ciency in application using MATLAB software.     

钢包滑动水口液压系统的局部改造

文章介绍了钢包滑动水口液压系统的工作原理,在分析了该系统的故障原因后,提出了对该液压系统的多项改造措施。     

双扉闸门卷扬式启闭机启闭力及动应力检测

采用高精度旁压式张力仪对双扉闸门卷扬式启闭机启闭力进行了现场检测,与通过应变计获得的吊耳应力计算的启闭力比较显示,两种方法吻合较好,检测结果可靠,均可应用于卷扬式启闭机启闭力检测。检测结果表明,闸门启闭过程中在小开度(0²m)时卡阻严重,启闭力和动应力脉动较大,检测工况下最大启门力已逼近启闭机额定容量,设计水位工况闸门启闭将存在重大安全隐患,须进行除险加固。     

例析微元法求解安培力的累积效果问题

当安培力是变力时,其在时间上或空间上的累积效果,可以用微元法结合图象法来求解。     

Tensile force correction calculation method for prestressed construction of tension structures

Factors such as errors during the fabrication or construction of structural components and errors of calculation assumption or calculation methods, are very likely to cause serious deviation of many strings＇ actual prestressing forces from the designed values during tension structure construction or service period, and further to threaten the safety and reliability of the structure. Aiming at relatively large errors of the prestressing force of strings in a tension structure construction or service period, this paper proposes a new finite element method （FEM）, the ＂tensile force correction calculation method＂. Based on the measured prestressing forces of the strings, this new method applies the structure from the zero prestressing force status approach to the measured prestressing force status for the first phase, and from the measured prestressing force status approach to the designed prestressing force status for the second phase. The construction tensile force correction value for each string can be obtained by multi-iteration with FEM. Using the results of calculation, the strings＇ tensile force correction by group and in batch will be methodic, simple and accurate. This new calculation method can be applied to the prestressed correction construction simulation analysis for tension structures.     

基于SWOT分析法对液压公司战略研究分析

小企业是我国国民经济中最活跃,最具有潜力的经济成分,激活小企业的发展对我国经济增长具有极其重要的意义。本文以上海液压有限公司为案例,结合战略管理理论,利用SWOT分析法对企业的优势、劣势、机会、威胁进行分析,对企业中存在的问题进行了诊断,以提升企业的核心竞争力。     

基于电模拟器的力控液压伺服系统DSP控制实验的研究

根据力控液压伺服系统的数学模型，设计了对象系统的电模拟器，并使用DSP作为数字控制器对力控液压系统的控制作了半物理仿真实验研究。实验研究结果表明，该半物理实验系统可以有效地用于控制算法的选择，可以丰富地展现控制效果，因此是一个良好的实验研究平台。     

A novel multi-objective optimization method for the pressurized reservoir in hydraulic robotics

The pressurized reservoir is a closed hydraulic tank which plays a significant role in enhancing the capabilities of hydraulic driven robotics. The spring pressurized reservoir adopted in this paper requires comprehensive performance, such as weight, size, fluid volume, and pressure, which is hard to balance. A novel interactive multi-objective optimization approach, the feasible space tightening method, is proposed, which is efficient in solving complicated engineering design problems where multiple objectives are determined by multiple design variables. This method provides sufficient information to the designer by visualizing the performance trends within the feasible space as well as its relationship with the design variables. A step towards the final solution could be made by raising the threshold on performance indicators interactively, so that the feasible space is reduced and the remaining solutions are more preferred by the designer. With the help of this new method, the preferred solution of a spring pressurized reservoir is found. Practicability and efficiency are demonstrated in the optimal design process, where the solution is determined within four rounds of interaction between the designer and the optimization program. Tests on the designed prototype show good results.     

新型场发射器件中栅极的化学刻蚀制备

为了得到碳纳米管场发射器件的三极结构,设计了一种新型栅极.在电极的制作过程中使用普通的丝网印刷方法,然后运用化学刻蚀的手段进行双面刻蚀制备出带有小孔阵列的栅极.在栅极制作过程中通过改变酸液刻蚀的时间和浓度,可以腐蚀出不同形状的小孔.运用扫描电镜(SEM)和红外光谱(IR)分析,得到小孔的尺寸、形貌和刻蚀液的成份,然后在三极结构上加电压显示出孔的亮度图像,最后对器件结构进行模拟,算出在电场条件下的电子从阴极拉到阳极基板的轨迹.模拟结果和实验结果一致,从而实现了对场发射三极器件的优化.     

水力机械综合试验台水力循环系统模块化设计

通过水力计算、系统集成创新,模块化设计水力循环系统,在有限空间内实现了大容量、灵活使用的水力循环系统,试验台满足IEC有关规程的规定,满足不同种类、不同结构、不同功能的水力模型试验机组的科研、教学实验要求,同时可拓展完成水力学试验,试验台具有高精度、高稳定性、多功能、灵活安装、便于使用特点。     

应用优化方法求解轴类零件同轴度误差

使用光学分度头或偏摆检查仪测量轴类零件同轴度误差时,一般沿用基于跳动原则进行数据处理。研究按优化计算方法的要求建立数学模型,利用MATLAB的优化工具箱求解同轴度误差,并通过示意图清楚地反映出被测量的几何特征,及评定准则的应用情况,对计算结论进行验证。测量方便,数据处理效率高,成本低。     

不同水力梯度对渗透系数影响研究

通过室内实验的方法,针对水力梯度对渗透系数的影响展开研究。实验筛分出粗砂、中砂、细砂分别进行不同水力梯度的渗流实验,并对每组实验数据进行分析、整理,通过计算机作图等手段研究水力梯度与渗透系数二者之间的关系。得到渗透系数随水力梯度变化的规律。     

内循环吹气吸收法测定沉积物中硫化物含量研究

酸性可挥发硫化物(AVS)是沉积物污染的一项重要指标。在吹气吸收法和冷扩散法基础上,自行设计内循环吹气吸收实验装置用于沉积物中AVS的测定,讨论了流量、时间、温度、含量对测定结果的影响。实验结果表明:内循环吹气吸收法具有装置简单、操作简便、反应时间短、准确度高等优点。实际测定了沉积物样品,回收率95%以上,该方法更适合沉积物AVS的常规测定。     

节段预制箱梁体外束极限应力增量计算方法

在考虑体内体外混合配束节段预制箱梁变形和破坏特征的基础上,提出推导节段预制箱梁体外筋应力增量的基本假设,建立节段箱梁梁体变形前后的几何关系,分3阶段详细揭示节段预制箱梁的受力机理,给出了每阶段体外筋长度的变化量,最终推导了双转向块、三分点加载情况下的节段预制箱梁体外预应力筋极限应力增量的计算公式。根据3根不同配束比的体内体外混合配束节段预制箱梁试验体外束应力增量测试数据,对提出的公式和另2种计算预应力增量的典型公式进行了验证,结果表明提出的公式计算结果与试验实测数据吻合较好。     

小型水稻灌区灌溉水利用系数测算方法

以节水灌溉模式下昆山市小型水稻灌区为研究对象,采用首尾法测量阴云圩灌区和天福灌区的灌溉水利用系数,探讨农业现代化进程中小型水稻灌区节水灌溉模式下灌溉水利用系数的测算方法,并分析这些测算方法的优缺点。结果表明:阴云圩灌区灌溉水利用系数测算方法的优势为测算成本较低、实用性较强,缺点为测量净灌溉水深时人工误差较大;天福灌区灌溉水利用系数测算方法的优势为自动化测量与数据自动远传,节省人力成本的同时,为精准灌溉、节水灌溉提供决策依据和数据支撑,缺点为设备成本及维护成本较高,采集长时段连续数据时仪器的稳定性有待提高。在经济条件许可的情况下,可推广采用流量计等自动测量方式来测量灌溉水利用系数。     

浅论物体受力分析的基本方法

物理受力分析的正确实施方法，“确定受力对象”是受力分析的出发点；找准每一个力是受力分析的关键点；选择适当的受力分析方法；受力分析的思维顺序；正确画出物体受力示意图；受力分析的审查．     

确定一维声子晶体带隙范围的模态方法

采用模态方法研究了一维杆状周期结构声子晶体的带隙特性,并通过理论计算得到了一维周期结构声子晶体的固有频率方程,解该方程确定出一维周期结构声子晶体的带隙范围。计算结果与数值模拟验证的结果十分吻合,说明该方法可行,用模态方法来解释声子晶体的带隙特性可以加快声子晶体向工程应用中转化的步伐。     

隐式差分法用于平衡扩散速率色谱模型的求解

为了稳定求解平衡扩散速率色谱模型,采用有限差分法建立了其迭代求解的隐式差分方程,讨论了其稳定性与方程误差,通过仿真计算考察了该差分格式的计算误差,并通过甘草苷与甘草素的分离实验进行验证。结果表明:该差分格式在线性及非线性体系下无条件稳定,计算误差小,准确度高;在非线性体系下,甘草苷与甘草素的计算色谱流出曲线与实验流出曲线吻合良好。     

常见外阴阴道外力损伤理化治疗方法探讨

文章研究了常见外阴阴道受到外力作用损伤理化治疗方法,重点探讨了物理治疗学在外阴阴道受外力作用损伤治疗方面的应用技术,强调了物理方法治疗常见外阴阴道受到外力作用损伤的注意事项。同时,强调了病因不同而采取的治疗手段不同,突出了治疗外阴受到外力损伤时,彻底止血、防治感染是治疗的关键。通过临床治疗效果对比,显示理化治疗比纯药物治疗效果更好。     

卧式容器强度计算中鞍座宽度的确定

本文通过具体设计的举例说明,给出了一种卧式容器强度计算中鞍座宽度的确定方法。